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authorQuentin Carbonneaux <quentin.carbonneaux@yale.edu>2016-04-04 11:34:26 -0400
committerQuentin Carbonneaux <quentin.carbonneaux@yale.edu>2016-04-04 12:55:32 -0400
commitf71206500c6693eed4393d72e8ab95d6a7e07d98 (patch)
treeb20f6af109b05291c8dc5848456c91372556ed6e
parent62c275fc75737e06844a89310bd18eccfbdfa573 (diff)
downloadroux-f71206500c6693eed4393d72e8ab95d6a7e07d98.tar.gz
cosmetics in sysv abi
A struct of size 0 is now marked as passed in memory.
All the ABI code assumes structs passed in registers
have size at least 8.  This could have an impact on
the alignment in the stack, but eh, I guess they are
rare.
-rw-r--r--sysv.c20
1 files changed, 9 insertions, 11 deletions
diff --git a/sysv.c b/sysv.c
index e0571e9..404c0ac 100644
--- a/sysv.c
+++ b/sysv.c
@@ -37,7 +37,7 @@ aclass(AClass *a, Typ *t)
 	a->size = sz;
 	a->align = t->align;
 
-	if (t->dark || sz > 16) {
+	if (t->dark || sz > 16 || sz == 0) {
 		/* large or unaligned structures are
 		 * required to be passed in memory
 		 */
@@ -265,7 +265,7 @@ selcall(Fn *fn, Ins *i0, Ins *i1, RAlloc **rap)
 	AClass *ac, *a, aret;
 	int ca, ni, ns, al;
 	uint stk, off;
-	Ref r, r1, r2, reg[2], regcp[2];
+	Ref r, r1, r2, reg[2];
 	RAlloc *ra;
 
 	ac = alloc((i1-i0) * sizeof ac[0]);
@@ -299,18 +299,16 @@ selcall(Fn *fn, Ins *i0, Ins *i1, RAlloc **rap)
 		} else {
 			if (aret.size > 8) {
 				r = newtmp("abi", Kl, fn);
-				regcp[1] = newtmp("abi", aret.cls[1], fn);
-				emit(OStorel, 0, R, regcp[1], r);
+				aret.ref[1] = newtmp("abi", aret.cls[1], fn);
+				emit(OStorel, 0, R, aret.ref[1], r);
 				emit(OAdd, Kl, r, i1->to, getcon(8, fn));
-				ca += 1 << (2 * KBASE(aret.cls[1]));
 			}
-			regcp[0] = newtmp("abi", aret.cls[0], fn);
-			emit(OStorel, 0, R, regcp[0], i1->to);
-			ca += 1 << (2 * KBASE(aret.cls[0]));
-			retr(reg, &aret);
+			aret.ref[0] = newtmp("abi", aret.cls[0], fn);
+			emit(OStorel, 0, R, aret.ref[0], i1->to);
+			ca += retr(reg, &aret);
 			if (aret.size > 8)
-				emit(OCopy, aret.cls[1], regcp[1], reg[1], R);
-			emit(OCopy, aret.cls[0], regcp[0], reg[0], R);
+				emit(OCopy, aret.cls[1], aret.ref[1], reg[1], R);
+			emit(OCopy, aret.cls[0], aret.ref[0], reg[0], R);
 			r1 = i1->to;
 		}
 		/* allocate return pad */